which sets the heap space to 40MB initially and a maximum of 256MB, and also specifies a maximum PermGen size of 256MB.

One of the most recommended options to use is to specify a specific JVM for Eclipse to run on. The following eclipse.ini demonstrates correct usage of the -vm option. Please take note that if your Java runtime is installed in a folder with spaces, you will need to escape it by enclosing your path with quotations appropriately.